1. Field of the Invention
The present invention relates to hoisting ramps for loading vehicles. Specifically, the invention is an apparatus for loading and unloading a motorcycle, snowmobile, other small recreational or utility vehicles, or other similarly sized loads onto the bed of a truck.
2. Description of Related Art
Several past inventors have developed various loading devices for small recreational vehicles. However, each have incumbent disadvantages.
For example, U.S. Pat. No. 3,877,594, issued to Donald L. Coakley, discloses a boat carrier using a beam mounted on top of a car attached to a walker beam, which was in turn attached to a boat trailer. To begin loading the boat, the walker beam is positioned so that it forms a ramp between the roof and the ground, and the trailer is positioned horizontally along the ground. The boat is placed on the trailer. The trailer is pulled onto the walker beam, which is then pulled onto the stationary beam. Once the boat's center of mass passes the end of the stationary rail, the boat, trailer, and walker beam tip over onto the stationary beam. However, allowing the boat to tip over in this manner can tangle the rope, and risk damage to the boat, loader, or car.
U.S. Pat. No. 4,653,671, issued to Stephen C. Pratt, describes a loading/unloading device for boats. The device uses a tilting ramp with a hinged rear section. The boat sits on a wheeled carriage. The ramp is extended, with the rear section sitting flat on the ground, and the boat is rolled down the ramp and into the water. While this is an excellent design for boats, it would be very difficult to use for other vehicles, for example snowmobiles, where snow would interfere with the carriage wheels.
U.S. Pat. No. 5,556,249, issued to Daniel M. Heine, describes a movable ramp used with a wheeled cart. The load is placed on the cart, which is then pulled up the ramp and onto the truck. As with anything which works by pulling a wheeled cart, this invention is of limited value on snow-covered ground.
U.S. Pat. No. 5,234,307, issued to Gerald W. Scott, describes a trailer for motorcycles designed to be used with a rollback tow truck. The rollback tow truck has a horizontal bed which can be moved rearward to form an inclined plane, and has a winch to pull a disabled vehicle onto the truck. This invention, of course, requires the use of a specialized truck.
Other inventions have been described each for another limited purpose. U.S. Pat. No. 4,274,788, issued to Luther M. Sutton, describes a loading device with a stationary frame mounted to a transporting vehicle, a ramp which can be raised onto the vehicle in a horizontal position, and a movable carriage. The vehicle to be transported is placed on the carriage, which is then pulled up the inclined plane. The inclined plane pivots into a horizontal position on top of the transporting vehicle, supporting the carriage. U.S. Pat. No. 4,932,829, issued to Robert W. Miller, also describes a movable inclined plane which, after a motorcycle is placed on it, can be moved either onto a truck bed or into a vertical position on the truck. U.S. Pat. No. 5,394,583, issued to Craig Plate, describes a motorized incline plane using two motors: one to move the inclined plane from a horizontal position on top of a vehicle, and the other to raise and lower the smaller vehicle to be transported. U.S. Pat. No. 4,749,317, issued to Phillip G. Daniel, describes a trailer for recreational vehicles having upper and lower levels. The upper level forms an inclined plane for loading vehicles onto that level using a winch.
U.S. Pat. No. 5,281,075, issued to Darrell J. Tatman and Albert D. Tatman, describes a pivoting ramp which, after a vehicle is driven onto the ramp, rotates to a horizontal position to transport the vehicle. International patent application no. PCT/SE87/00621, published under the Patent Cooperation Treaty, describes a trailer which tilts back to form a ramp for loading vehicles onto it.
Because each of the above noted inventions have specific functions, each is limited is some way. Some of the inventions discussed above require modification of the transporting vehicle before use, unlike the present invention. Many would not be likely to work properly in the snow-covered regions where a snowmobile would likely be used. Many also provide very little control over the path of the carriage and load, allowing the possibility that the loading device, vehicle to be transported, or the transporting vehicle, will be damaged. The present invention avoids these disadvantages and therefore may be more applied a larger universe of problems heretofore addressed by inventions limited in scope.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.